Spark-plug.



Patented May 21, 1918 compact and vdependable, and arran may be UNITEDSTATES PATENT OFFICF PAUL O. DEPEW, 0]! CHICAGO, ILLINOIS SPARK-FLUO-Specification of Letters Patent.

Patented May 21, 1918.

Application filed Inn: 9, 1815. Serial No. 33,008.

One of the ob ects of my invention is to provide a spark plugconstructed and operated so that the spark at the terminals will at alltimes be maintained clean, means being provided for preventing theaccumulation thereon of carbon deposit.

A further object of my invention is to provide a s ark plug comprisinmeans for automatica y passing air into e cylinder 'duiingzthe suctionstroke of the piston.

rther object of my invention is to provide a simple ark Ehhg comprisingmwdeans forprimingt e cy 'n er in case of n V Ingeneral the object pf myinvention is to provide a spark plug which is aim is, so terminals willbe main-.

that the rk spa ga at the air will be autotained clean, so

.matically admitted during the suction stroke of the cylinder, and sothat the cylinder companymg drawings Fi re 1 is an elevation of a sparkplug which embodies features of my mvention; Fi 2 is a centrallongitudinal section of t 0. p rk plug; Fig. 3 is an end view thereof;Fig. 4 1s a central transverse section thereof; Fig. 5 is a centrallongitudinal section of a modified form of sparkplu-gi The spark plugwhich I i ustrate in this instance as my preferred form comprises acasing 5, the casing having external threads 6 at one end, for thepurposeof screwi' into the casingof the c linderin the ordinary manner,internal reads 7, and-a central longitudinal passageway 8' extending theentire length of the casing. The pas-- sageway 8 is materiallyrestricted at the lower end of the casing so as to form an aperture 9the walls of which form the grounded terminal of the spark gap.

Threaded into the threads 7 of the upper endofthecasingistheprotectingcasmg primed when desired. In the ac-' ivardlythrough cylinder 10. An annular insulating member 11 is fitted into thecentral portionvof the casing and is held in place by means of theproltecting casing 10, gaskets 28 preventing leakage, in an ordinarymanner. The insulating member may be made of an suit able material; Iprefer porcelain or the pug pose.

wed in the member 11 is an annular member 12 having a valve seat 13ground on the lower end thereof. This member 12 may be cast in theporcelain 11 or fixed therein in any suitable manner. A valve 14 isadapted to coaot with the valve seat 13, and has a valve stem 15projecting upwardly through member 11 and through a guide piece 16 whichis fixed in the porcelain. The stem 15 is free to move longitudinall anda compression spring 172encircles t e stem, between the grade 16 and thenut 18 threaded onto the valve stem,- and thus tends at all times tohold the valve '14 in contact with the seat 13. Extcndin downwardly fromthe valve 14 is a rod 1 the lower end, of which forms the inner terminal31 of the spark gap.

In operation, at the time of the suction j stroke of the piston thereduced ressure m the cylinder, and hence in the c amber 29 of thepassageway 8, allows the ressure of the external air to overcome t oupward tendency of the spring 17 and to force the valve 14 downwardly,and thus more or less air is'allowed to enter the cylinder through thepassageway 30, the amount depending upon the tension of the spring 17,as controlled by the nut 18. The air passes down- 'the chamber 29 andthe 9, and is thus forced at n-high speed a inst the spark gap terminals31 and 32, lowing therefrom any particles of carbon that may haveadhered thereto at the time of the last explosion. \Vhen the comressionstroke occurs the gas in the cylinder is forced upwardly through theaperture 9, forcing the valve 14 cl&ed, and a the same time forcing thegas against the spark gap terminals and tending to further clean thesurfaces thereof. Finally when the explosion occurs gas is forcedupwardly through the aperture 9 and then downwardly again, as thepressure in the becomes less than the pressure in So that there is aconback opening the passageway 29. tinual vibration of air at high speedand forth throu h the a erture 9 tending to clean the sur aces of t espark gap terminals.

Although the particular arrangement shown is not material to myinventlon, yet in this instance I have connected, the wire 20 whichleads from \the magneto to the rk plug, to the upper end of the valve 5In 15, immediately above the nut 18, by means.of a washer 22 held firmlyagainst the terminal 21 of the wire by a spring 23 held compressed bymeans of the clip 24 and nut 25. This pressure of the spring isBuflicient to hold the terminal 21 in place; but it m'ay be removed orreplaced by forcing the terminal from, or in, between the nut andwasher.

If it is desired to prime thc cylinder, it is necessary only to pour thegasolene through the aperture 26 of the protecting casing. If desiredthe valve stem may then he forced dmvnwardly, so as to allow thegasolenc lo pass inwardly; or the suction stroke of the piston ma bedepended upon to open the valve and a low the gasolene L0 ass inwardly.In either case the gasoene will ass downwardly and will come in contactwith the surfaces of the spark gap terminals, and will assist in keepingthe surfaces clean.

By the arrangement of parts shown and described it is evident that theprotecting casing 10, the porcelain 11, andthe inner spark gap terminals31 may all be removed without removing the casin 5 from the cy'linder;and thus all parts 0 the spark plug maybe examined or replacedconveniently;

and the external terminal 32 of the s ark gap may also be cleaned asdesired wit rout removing the casing 5.

Fig. 5 illustrates a modified form of spark lug. which nlso'embodicsfeatures of'my invention. The air and gasolcne'inlet casing 35 isattached to the side of the casin 36 of the plug; and the valve 37 ismounts as indicated in the casin 35, V Although I have descri d withsomc-particularity devices whichembody the features of my invention, yetit is to be ur'idorstood that various modifications may be made thereinby those skilled in the art without departing from the svirit of myinvention as indicated by the fo lowing claims.

I claim as my invention- 1. A spark p ng, eomprisim a lube a. conductorslidably mounted in the bore of said tube; a valve fixed to'sn-idconductor; a member fixed in said tube and encircling said conductoradjacent said valve, said member having a valve seat, the walls of saidseat diverging downwardly; and yielding means tending to-hold said valveagainst conductor upwardly and to old the valve against. the seat; andmeans for connecting an electric conductor to the upper end of saidconductor.

3. A spark plug comprising a casing, said casing having a passagewaytherethrough, an insulation bushing in sai passageway, a member mountedin said bushing and ving a valve seat on its lower end, said bushingextending a material distance above said member, a conductor slidnblymounted in said bushing, a valve fixed to said conductor below saidvalve'seat, an electric conductor detachably connected to the upper endof said former conductor, and means tendin to force the said formerconductor upwar ly and to hold the valve against said seat.

4. A spark plug comprisingla casing, said casing having a passagewayerethrough, a member mounted in said passageway, said to force themember having a downwardly diverging valve seat on its lower end, aconductor pass--= iug through said member and said passageway, the lowerend of said conductor being adjacent the 'walls of said casing, a valvefixed tothe said conductor below said valve seat, and yielding meanstending to force and to hold the the conductor upwardly valve agaiustthe seat.

e 5. A spark plug comprising ductor slidably mounted in ti a'tube, acone bore of sa d tube, a yalve fix'ed to saidcondiictor, ameniber fixedin said tube and encircl ng said conductor adjacent'said valve, saidmember having a valve seat,-the walls of said valve seat divergingdownwardly, and yielding means tending to hold said valve against saidseat, lhe lower end of the bore of said lube being materiallyrestricted, the inner surface of the said restricted lower end beiugformed to converge downwardly to the end opening, said valve arranged toopen by an cxress external pressure.

In testimony whereof, I hereunto set my hand.

PAUL C. DEPEW.

